Settle amount in empty beer glass? (3)
I believe the answer is:
opt
'settle' is the definition.
(settle or decide on something)
'amount in empty beer glass?' is the wordplay.
'amount' becomes 'p' (I am not sure about this - if you are sure you should believe this answer much more).
'in' is an insertion indicator.
'empty' says to hollow out the word (remove centre letters).
'beer glass?' becomes 'object' (beer glass is a kind of object).
'object' with its middle taken out is 'ot'.
'p' going within 'ot' is 'OPT'.
Can you help me to learn more?
(Other definitions for opt that I've seen before include "Choose from pot" , "Make a choice" , "Pick from pot" , "Plump for" , "Have preference for something" .)